<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			//var x=10;
			//console.log(x);
			//{//代码段
				//var x=100;
				//console.log(x);
			//}
			//console.log(x);
			let x =10;
			console.log(x);
			{
				let x=100;
				console.log(x);
			}
			//代码段中，let定义变量作用域，代码段结束，里面的x也结束
			console.log(x);
			
			//js只有变量，没有常量定义，es6定义常量
			var sysname="学生管理系统";
			console.log(sysname);
			sysname="mis";
			console.log(sysname);
			
			const p1=3.14;
			console.log(p1);
		</script>
	</head>
	<body>
		<h3>es6的新标准</h3>
	</body>
</html>
